Multiple telephone-transmitter.



P. W. WOOD. MUI IT i-FLE TELEPHONE TRANSMITTER. I 'APPLioATI'mw fin-rmJULY 16, 19061 94 5 069, Patented Jan. 4,1910.

2 SHEETS-SHEET 1.

F. W. WOOD. MULTIPLE TELEPHONE TRANSMITTER.

APPLICATION FILED JULY L6,1906.

Patented Jan.4,1910.

2 SHEETSSHBET 2.

w M 2 Ma fa WP M UNITED STATES PATENT OFFICE.

' FRANK W. WOOD, OF NEWPORT NEWS, VIRGINIA, ASSINOR TO CHARLES CORY ANDJOHN M. CORY, 9F NEW YORK, N. Y.

WI'UL'J'.IIPILIE TELEPHONETRANSMITTER.

Specification of Letters Patent.

Application filed July 16, 1906.

Patented Jan. 4, 1910.

To all whom it may concern:

. stationed at a given point shall he received at a plurality ofdifferent stations, as by the pilot, the engineer, etc.

It has heretofore been proposed to distribute speech from a common pointto a plu- ,rality of receiving points by connecting the receivers at thelatter points in branch circuits through the transmitter. Such anapparatus, however, does not produce distinct and loud sounds in thereceivers.

It is an object of the present invention to provide a system andapparatus whereby speech transmitted from a single point may be loudlyand distinctly enunciated at a pluralit-y of receiving points] This isaccomplished by providing a plurality of transmitters having a-commonmouthpiece, each transmitter being connected with a receiver at areceiving point as distinguished from several receivers being connectedto one transmitter.

A further object of the invention is to render the transmittingapparatus water-tight and protect all parts liable to corrosion from theaction of injurious influences, thereb rendering the apparatusespecially suitable for service on board ship where it may besubjected-to dampness and salt air.

It is a further object of the? invention to improve details ofconstructionof the appargtus and further objects will appear hereinater. I

The invention is illustrated in the accompanying drawings of which Figure '1 is a central vertical section of a transmitting instrument. Fig. 2 is a view of the top portion of the back of the transmitters, thelower portion being broken away. Fig. 3 is a front. view of the lowerportion of the transmitters, the top portion being broken away. Fig. iis a section on the line of Fig. 1. Fig. 5 is a section of transmitteron the line (5-6 of Fig. 2, and Fig. 6 is a diagram of the electricalcircuits.

Referring to the drawings, the apparatus comprises a casing A withinwhich are mounted a mouthpiece B, transmitters C, terminals D for thetransmitter contacts, a switch E for making and breaking circuit throughthe transmitters as Will be hereinafter set forth. 'To the transmittersof the instrument just described are connected the different receivingstations F, as shown clearly in Fig. 6, a battery or other source ofcurrent G serving to supply the transmission current.

The mouthpiece B comprises a funnelshaped device having an opening 1 atits smaller end through which the sound waves are received, this openingbeing normally closed by means of a IidQ'hinged at 3. This lid istightly fitted so as to exclude air and moisture from the mouthpiece. Atthe large end of the funnel is mounted a supporting plate 4 in which thetransmitters are mounted. This plate is perforatedas shown, there beinga ledge 5 (see Fig. 5) at the front of each perforation on which thediaphragm is mounted. To the back of the plate 4 is cured a supportGtowhich one of the microphonic contacts 7 is secured. The othermicrophonic contact Sis secured to the main diaphragm 9 which ispreferably of aluminum but may be of iron or other suitable material.This diaphragm is secured o e inner side of the ledge 5 by any suitablemeans, an india rubber band 10 surroiuiding its edge and insulating itfrom the ledge. In front of the diaphragm 9 is mounted a protectivediaphragm 11 which serves to shield the main diaphragm from the effectsof atmosphere or other influences which may be injurious and ispreferably of copper foil which, for greater security, should be coatedwith-waterproof varnish. The microphone.

contacts may be of carbon and constructed Serial No. 326,350.

in any one of the Ways which are well known to persons skilled in theart. The support 6 at the back of each transmitter has recesses 12 and13 through which extend the damping springs 14 and 15. These dampingsprings are each secured at one end to the support 6 and at the otherend bear upon the edge of the diaphragm 9, thereby damping thevibrations of the diaphragm in a manner as is well understood. The endsof the springs which bear upon the diaphragm are provided with rubbertips 16 and 17 whereby they are insulated from the diaphragm and freecircuiting ofthe microphone contacts is prevented. The support 6 ispreferably Z-shaped as shown and the mounting of the damping springs asde scribed contributes to the compactness of the apparatus.

The switch E comprises normally separated contacts 18 and 19 adapted tobe closed by a plunger 20 sliding in a support 21 se cured to the casingA. This plunger may be actuated from the exterior of the casing byressure exerted upon its outer end, a flex] le sheet or membrane 22 ofrubber or other suitable material covering in a watertight manner theaperture 23 in the casing A through which the plunger is operated. Thecontacts D are suitably mounted upon an insulating st. lp' 2% secured tothe casing A. An opening 25 is provided for the entrance of conductorsin a water-tight manner.

Referring particularly to Fig. 6, it will be seen that all of thetransmitters C have one of their contacts connected through switch Ewith one terminal of the battery G. The other contact of eachtransmitter. is individually connected with one terminal of a receiver26 at one of the stations F, the other terminal of the receiver beingconnected With the other terminal of the battery G, each transmitter 27at a station F is connected with one terminal of the battery G and whenthe switch28 is closed, is connected with the other terminal of thebattery Gr through the receiver 29 at the central transmitting station.The construction of the transmitters and receivers 26, 27 and 29 may beof any well known type and need not be further referred to, as may alsothe switches 28.

The operation of the apparatus may now be set forth as follows: If theperson at the central transmitting station desires to transmit amessage, the lid 2 is opened and the switch E is closed. The closing ofthe switch E operates to close the circuit of each of the transmitters Cthrough'a receiver at one of the stations 1 and through thebattery (lr.Upon the entrance of speech waves in the mouthpiece and actuation of thediaphragms in the usual manner the microphonic conout the interpositionof other apparatus whereby the resistance of the circuit would beincreased and the strength of the current diminished. If now a party atone of the stations F desires to communicate with the centraltransmitting station, he closes his switch 28 whereupon the transmitterat that station is connected in series with the battery G and thereceiver 29 at the central station. In this case also it will be seenthat no devices are interposed in the circuit with the transmitter andreceiver across the battery. Upon the apprisal of the person at thecentral transmitting station by means of his receiver 29 that a party ata station F desires to communicate with him he may release his plunger20, thereby permitting the switch E to open, thus cutting off circuitswhich might divert current from his receiver. Upon a like principle eachparty at the station F opens his switch 28 to prevent diversion ofcurrent from the receivers 26 when the central station is communicatingwith the outlying stations.

\Vhile the invention has been described in connection with microphonictransmitters, it will be understood that it may also be carried out bymeans of magneto transmitters.

Other variations and modifications of the structure shown might beemployed without departing from the spirit of the invention,

and it is not, therefore, limited to the structure shown.

\Vhat I claim is:-

1. The combination with 'a transmitting apparatus comprising a casing, aplurality of transmitters therein, and a common funnel shaped mouthpiece for said transmitters. the smaller end of said mouth pieceprojecting through a wall of thecasing and the large end embracing saidtransmitters, of a plurality of receivers, and an independ ent circuitconnecting each of said transmitters with one of the receivers.

2. The combination with a transmitting apparatus comprising a casinghaving front and rear walls, a plurality of transmitters thereinadjacent the rear wall thereof, anda funnel shaped mouth piece arrangedwith its large end embracing said transmitters,-

and communicating at its small end with an opening in the front wall ofsaid casing, of a plurality of receivers, one for each transmitter, andconnections between each transmit ter and its corresponding receiver.

3. The combination with a transmitting apparatus comprising a casing,and a plurality of transmitters therein, each transmit ter having adiaphragm, and means actuated by said diaphragm for varying theresistance of an electric circuit, of a common, funnel-shaped mouthpiece embracing said transmitters, the small end of said mouth piecepassing through the casing and the large end embracing saidtransn'iitters, a plurality of outlying receivers, one for eachtransmitter, and an independent connection between each transmitter andone of said receivers.

4. In a telephone system, the combination with a central transmittingstation comprising a plurality of transmitters having one commonterminal, a source of current to one side of which the common terminalof said transmitters may be connected, a single receiver associated withsaid transmitters and a series circuit in which said receiver and sourceof current are connected, ot' a plurality of outlying stations eachcomprising a receiver and transmitter, each of such transmitters beingconnected in multiple across said series circuit, and each of suchreceivers having one terminal connected to one side of said circuit, andthe other terminal connected with the other terminal of one of saidfirst mentioned transmitters 5. In a telephone system, the combinationwith a central transmitting station com 'rising a plurality ofindependent transmd ters having one common terminal, a single receiverat such station associated With said transmitters, a source of current,a series circuit in which said receiver and source of current areincluded, and a connection extending from the commoniterminal of saidtransmitters, and tapping said circuit between said source of currentand receiver, of a plurality of outlying stations each comprisingatransmitter and receiver, each of said receivers being c onnectedbetween one side of said series circu t, and the other terminal of oneof the central station transmitters, and said outlying. receivers beingconnected across said series circuit, and means for open- -ductorsconnecting the other transmitters ing the circuit of .any of saidtransmitters when not in use.

6. In a telephone system, the combination with a central transmittingstation comprising a plurality of transmitters, a source of electriccurrent, a sin 'le switch for connecting one terminal of all of saidtransmitters with one terminal of said electric source, a phiralityotreceivers, a conductor connecting the other terminal of each of saidtransmitters with a terminal of one of said receivers, means forconnecting the other terminal of each receiver with the other terminal.of said electric source, the said con=.. ductor connecting eachtransmitter and receiver being independent of the similar con-1 ing eachof said pa'rallel transmitter circuits.

7. The combination with a plurality of transmitters, a source ofelectrical supply, a plurality of receivers, means for connecting saidreceivers and transmitters in branch circuits in parallel across saidsource of supply, each branch circuit containing atransnutter andreceiver connected in series, means for simultaneously breaking thecircuit of said source through all of the transmitters and receivers,the conductor for connecting the receiver and transmitter in each ofsaid branch circuits being independent of the similar conductors in theother branch circuits, a plurality of independent transmitters connectedin parallel and in series with a single receiver across the said source,and means for independently breaking each of said parallel transmittercircuits.

8. The combination with acentral trans mitting station comprising aplurality of transmitters and a receiver, of a source of electricalsupply, a plurality of outlying stations each comprising a transmitterand a receiver, of means for connecting the transmitters at the saidcentral transmitting station and the receivers at the said outlyingstations in parallel across said source, each branch circuit containinga transmitter and receiver connected 'in series, and means forconnecting the transmitter at any of the said outlying stations inseries with the said receiver at the central transmitting station acrossthe said source.

9. The combination with a central transmitting station comprising aplurality of transmitters and a receiver, of a source of electricalsupply, a plurality of outlying stations each comprising a transmitterand a receiver, of means including a switch for connecting thetransmitters at the said central transmitting station and the receiversat the said out-lying stations in parallel across said source, eachbranch circuit containing a transmitter and receiver connected inseries, and means including a switch for c0nnecting the transmitter atany of the said outlying stations in series with the said receiver atthe said central transmitting station across the said source.

10. In'a telephone system, the combination with a'central transmittingstation comprising a plurality of transmitters, a common mouthpiece forsaid transmitters, and a receiver, of a plurality of outlying stationseach comprising a transmitter and a receiver, a source of electricalsupply, means 'tor connecting the transmitters at the said centraltransmitting station and the receivers "fat the outlying stations inparallel'circuits across saidSource, each of the branch circuitscontaining a transmitter and a receiver connected in series, and meansfor connecting any of the transmitters at any of the said outlyingstations in series with the receiver at the'said central station acrosssaid source.

In testimony whereof I have hereunto set my hand 1n presence of twosubscribing Wrtnesses. FRANK XV. WOOD.

Iitnesses J. E. VARREN, E. W. HOUSE.

